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Old 28-04-2016, 10:16 AM
rotrex rotrex is offline
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Join Date: Jan 2014
Location: Germany
Posts: 187
Default Re: Nozzle spray angle...

Flow velocity is the fastest on the inside of a bend.
Droplets do not like to take bends. They will hit the wall and wet it.

This is the reason fuel injectors are spraying straight into the inlet port.
They are not mounted before any bends. In the old days of throttle body injection the manifolds were first designed for wet flow and they were heavily heated to let that wet fuel film on the intake plenum wall evaporate.

Water evaporates about 10x slower than methanol and much much slower than gasoline.
If you want water meth as droplets in the cylinder and not as a stream along the wall you have two choices.
Either have the nozzles in the straightest section before the inlet ports of the engine or mount the nozzle as far away from the engine as possible. In the latter case there is more time to evaporate, even if streaming along the wall. In the first case, the highest percentage of droplets will make it into the cylinder.

Calculate the g-forces in a bend of your radius at WOT and max flow. You will find numbers of 1000G and more. These are typical numbers found in vortex water separators to remove water droplets from natural gas.

In the end all loss of fluid can be compensated by injecting more or use of a higher percentage of methanol. It evaporates on the wall as well as in the air.

IMHO inject as suggest by parmas straight into the SC and then in the straight section leading into the intake plenum. Your center cylinders will receive more spray than the outer ones as the drops have to take more bends. Little you can do about it except going for a direct port set-up.

Last edited by rotrex; 28-04-2016 at 10:19 AM.
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